This application claims the priority of German patent document 198 39 349.0, filed Aug. 28, 1998, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a vehicle immobilizing device having an authentication element which can be carried by an authorized vehicle operator.
Previous immobilizing devices of this type in cars have generally comprised only mechanical keys/ignition locking systems. That is, the immobilizer control unit on the vehicle was formed only by a mechanically operable ignition lock, which could be operated by mechanical keys carried by the user as authentication elements via the associated actuation communication channel. In such systems, in order to switch on the general vehicle power supply in a first stage the mechanical lock is switched to the so-called xe2x80x9cradio positionxe2x80x9d or standardized terminal 15R; in a second stage, the ignition is switched on via standardized terminal 15 and, in a third stage the engine starting unit is activated via standardized terminal 50. Once the engine has been started, the key returns to the ignition-on position.
Such mechanical immobilizing devices are nowadays increasingly being replaced, or at least supplemented, by electronic immobilizers. These modern, electronic driving authorization systems do not require a mechanical lock, but use a wireless actuation communication channel for authentication communication. A first type of such systems uses electronic keys as authentication elements, by analogy with classical mechanical key and lock systems. Depending on the system design, control buttons are provided on the electronic keys in order to initiate an immobilizer actuation communication which requires authentication (that is, a check of the driving authorization), or such communications are carried out via a close-field communication channel. In the latter systems, the key is introduced into a key holder provided on the vehicle in the form, for example, of an electronic ignition lock.
So-called xe2x80x9ckeyless-goxe2x80x9d systems are also known and are gaining increasing attention at present. In these systems, authentication elements, such as smart cards or transponders carried by the vehicle user, require no action by the user. Authentication communication in such systems are initiated on user request, or automatically when a valid authentication element is in the effective area of the associated actuation communication channel. The effective area is, typically, defined by the transmit/receive range of an associated antenna apparatus.
In addition to ignition key/ignition lock units which check driving authorization, systems may also be provided for switching the vehicle engine off automatically or when requested by the user, and for switching it on again when requested by the user. Such systems generally include an appropriate control element arranged on a transmission selection lever. See the German Utility Model Documents DE 79 27 688 U1, DE 82 19 522 U1 and DE 87 08 510 U1 as well as Laid-Open Specification EP 0 314 611 A1. These known devices are used to switch the engine off in order to save fuel when the vehicle is temporarily stationary, for example at junctions or in a traffic jam. In this case, the ignition remains switched on while the engine is temporarily switched off (that is, driving authorization is not inhibited). In a further development of this system type in the journal publication B. Priemer, Kleines Wunderxe2x80x94Vorstellung Mercedes S-Klasse [A small miraclexe2x80x94Introduction to the Mercedes S Class], auto motor sport, 15/1998, page 16, it is proposed that the vehicle no longer be started by means of an ignition key but by means of a small button which is located on the control gate of an automatic transmission selection lever.
One object of the invention is to provide an immobilizing device of the type mentioned above, which, if required, can be in the form of a keyless-go system, and in which immobilizer actuation communication processes which require authentication can be initiated on user request with a high level of user convenience, and/or which can be activated with a high level of convenience of use by the vehicle driver after enabling engine starting.
These and other objects and advantages are achieved by the vehicle immobilizing device according to the invention in which actuation communication processes which require authentication (those which are accompanied by a check of user authorization) are carried out on user request. For this purpose, an appropriate immobilizer operating element arranged on the vehicle can be operated without any authentication element (that is, without using the authentication element itself).
The invention is also suitable, in particular, for configuration as a keyless-go system, in which the user needs only carry his or her authentication element, for example a smart card. Actuation measures for driving authorization can be requested by operating the immobilizer operating element from the driver""s seat. The authentication process initiated in this way is completed successfully, provided that the authentication element, which is carried by the driver and is located in the effective area of the actuation communication channel, is valid for the associated vehicle.
According to one embodiment of the invention, the immobilizer control part enables driving authorization and causes the engine to be started, via an appropriate authentication communication, only when the user operates the brake pedal and keeps it depressed. In this embodiment, engine starting is enabled by a successfully completed authentication process on request via an immobilizer operating element, and comprises the process of switching on the previously switched-off ignition. This device as well is highly suitable for configuration as a keyless-go system, in that engine starting is enabled automatically or on user request via the authentication element carried by the user.
According to another embodiment of the invention, the immobilizer operating element (by means of which the user can initiate immobilizer actuation communication processes which require authentication) comprises a button arranged on the transmission selection lever, thus allowing particularly convenient operation by the driver.
In still another embodiment, the immobilizer operating element is a multistage button element. A first button stage is used to initiate an ignition switching-on process, which requires authentication, while another button stage allows the ignition to be switched off.
Yet another embodiment of the invention includes a multistage button element as an immobilizer operating element. One button stage is used to switch the ignition on, which requires authentication, while another button stage is intended to initiate (activate) engine starting. In conjunction with a keyless-go system, for example, such a button system can carry out all the functions of conventional ignition-lock systems.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.